1. Field
One or more embodiments relate to a polymer and a polymer actuator including the polymer, which is suitable for use in mobile devices and applied to various areas such as polymer microelectromechanical systems (MEMS) and biology.
2. Description of the Related Art
Polymer sensors and an actuator using a polymer are being widely used in various areas. For example, with regard to highly efficient camera modules for mobile devices, the need of large displacement actuators has increased in order to realize auto focus and zoom functions. An actuator which is made of a ceramic piezoelectric material shows its maximum strain of about 0.1%, whereas an actuator using a polymer shows its maximum strain of about 5%. Thus, research into an actuator that uses a polymer is being actively conducted.
A polymer employed in an actuator includes a ferroelectric polymer, for example, polyvinylidene fluoride (PVDF). PVDF is thermoplastic and has a melting temperature of about 150° C. to about 160° C., and, thus, fragile at high temperatures. Accordingly, a polymer actuator including the PVDF polymer may not stand a solder reflow condition of about 200° C. or above and thus it is difficult to perform a batch process using a solder reflow process. In addition, a relaxor ferroelectric polymer material, such as poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) and poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)), has a melting temperature of about 120 to about 130° C., which is lower than that of the PVDF, and thus is more fragile at high temperatures. Accordingly, use of the polymer actuator using the relaxor ferroelectric polymer material is limited at high temperatures.